As to systems using storage devices such as SSDs (Solid State Drives), with the scale of the systems increasing and the processing speed increasing, reduction in overhead associated with interruptions by storage devices as responses to instructions from a host is required of the systems.
As data transfer in the storage device, there is random transfer which transfers individually data each of a size no larger than a data-transfer unit as well as sequential transfer. In the sequential transfer, by executing one interruption collectively for multiple commands, with improving throughput, overhead of interruption processing can be reduced. In contrast, in the random transfer, latency is often an index of performance. Accordingly, the number of commands to be dealt with together needs to be decreased or the time-out interval from when a command is received until an interruption is generated needs to be reduced.